1. Field of the Invention
Method and apparatus for injecting a sealant material into a crack or pipe joint from the piper interior using an inflatable device.
2. Description of the Prior Art
Storm drains, sewers and various supply pipes are typically manufactured from concrete, clay, steel, plastics or similar materials and are assembled in sections. Such conduits generally are buried under ground. Because of the nature of the materials from which the pipes are constructed and because such pipes tend to shift with the swelling and movement of the ground due to frost and hydrostatic forces, leaks frequently occur in such pipes either by the cracking of the pipe material or by separation of the pipe sections at their joints.
Conduits of this type generally vary in size from several inches up to ten feet in diameter. In the past when pipes of this type have cracked or become separated at their joints such that leaks in the pipe occur, it was frequently necessary to excavate the area surrounding the pipe to repair it from the exterior or to replace the pipe section which was damaged.
In certain instances, it has been possible to repair small diameter pipes by using remote apparatus which is pulled through the pipe on a cable. Such apparatus may incorporate expandable devices and injection systems which force sealing material into the crack or joint which is being repaired. These devices are generally designed for use in pipes of relatively small diameter. Because such devices must be remotely controlled, it is necessary to provide relatively complex and expensive support equipment for guiding and operating the sealing device from outside of the pipe. Such equipment has necessitated the use of personnel having a high degree of skill and training.
In addition to being repaired by excavation and replacement of damaged pipe sections, larger pipes are frequently repaired by the use of caulking guns or similar devices which are carried into the pipe by work personnel and used to inject a sealant material into cracks or pipe joints. However, hand-held caulking devices have very limited usefulness in the repair of deep cracks in the pipe casing, in the repair of extended cracks or the packing of pipe joints. In the case of deep or extended cracks and joint openings, it is not possible to project a large amount of caulking material deep into the void because means are not available to apply suitable pressure to the caulking material. The pressure which is provided by the caulking gun is lost at the gun nozzle and thus continuous pressure can not be applied to the caulking material to pack it deeply into the joint or to pack large amounts of the caulking material.
Present technology provides various two-component caulking materials which utilize two substances that expand when combined. Such materials would be extremely useful in sealing cracks and joints in various pipes if means were provided to adequately isolate the crack or joint area so that the pressure which the two-component sealant builds up when mixed is suitably contained to force the caulking material into the void or joint. Presently available sealing devices generally do not provide means for adequately isolating and sealing voids or joints in large diameter pipes so that these two-component expandable sealing materials could be utilized.